PHYSICO-CHEMICAL REGULATN OF ENZYMES IN LIPID METABOLISM

脂质代谢中酶的物理化学调节

• 批准号: 3368309
• 负责人: Howard L. Brockman
• 金额: $ 18.19万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-03-01 至 1996-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3368309
• 关键词: biological signal transduction; cofactor; enzyme activity; enzyme mechanism; enzyme substrate; lipase; lipid metabolism; lipid transport; membrane model; pancreas enzyme; phase change; phosphatidylcholines; phosphoglycerides; phospholipase A2; surface property

The goal of this project is to determine the mechanisms by which the phospholipase A2 and colipase-dependent lipase from pancreas are regulated at lipid-water phase boundaries. It is hypothesized that a major factor in this regulation is the lateral organization of lipids in the plane of the lipid-water interface. Such regulation is expressed both at the level of enzyme partitioning to the interface from aqueous solution and at the level of catalysis within the interfacial plane. Emphasis is on understanding the roles of lipid composition, packing, surface potential and the protein cofactor, colipase, in the initiation and maintenance of phosphatidylcholine and glyceride hydrolysis, i.e., (phospho) lipolysis. To identify the extent to which organization influences (phospho)lipolysis, enzyme adsorption to and catalysis in model phospholipid-glyceride interfaces will be measured. This will include both initial rate measurements and measurement of the extent of adsorption and catalysis. The interfaces will be monolayers and bilayers which are highly controlled with respect to lipid composition, packing density and electrical properties. By correcting results for the contribution of the usual intensive variables of enzyme and substrate concentrations, organization-dependent effects will be revealed. When examined on a lipid composition basis, these corrected data will reveal the composition at which the postulated critical transition occurs and how relative lipid cluster size changes as the critical composition is approached. In related experiments, average cluster size will be measured. These studies address the regulation of interfacial reactions which occur not only in the intestine but in all tissues. Such reactions are involved in inflammatory processes, lipid transport and signal transduction. Their control, or lack of it, contributes to the pathology of diseases such as atherosclerosis and arthritis.

本项目的目标是确定 来自胰腺的磷脂酶A2和辅脂酶依赖性脂肪酶， 在脂-水相边界调节。 据推测， 这种调节的主要因素是脂质的横向组织， 脂-水界面的平面。 这样的规定， 在酶从水溶液分配到界面的水平上 溶液和在界面平面内的催化水平。 重点是了解脂质组成，包装， 表面电位和蛋白质辅因子，辅脂酶，在启动 并维持磷脂酰胆碱和甘油酯水解，即， （磷酸）脂解。 确定组织影响的程度 （磷酸）脂解，模型中的酶吸附和催化 将测量磷脂-甘油酯界面。 这将包括 初始速率测量和 吸附和催化。 界面将是单层， 相对于脂质组成高度受控的双层， 堆积密度和电性能。 通过纠正结果， 酶和酶的通常强度变量的贡献 底物浓度，组织依赖性的影响将是 揭示 当检查的脂质组成的基础上，这些纠正 数据将揭示假设的临界 以及相对脂质簇大小如何随着 关键成分接近。 在相关实验中，平均 将测量集群大小。 这些研究涉及界面反应的调节， 不仅发生在肠道，而且发生在所有组织中。 此类反应 参与炎症过程、脂质转运和信号传导 转导 他们的控制，或缺乏控制，有助于 动脉粥样硬化和关节炎等疾病的病理学。